Letters from Northern Ballet Theatre’s late Artistic Director Christopher Gable are among the archival material destroyed in a devastating fire at the company’s temporary headquarters in Leeds on Friday.

Other historical documents and contracts for forthcoming seasons have also disappeared in the fire, which is suspected to have been started by arsonists. Smoke and water have seriously damaged costumes for the company’s production of Romeo and Juliet, due to begin a UK tour in three weeks time.

The fire started early on Friday morning at the company’s temporary headquarters in a former girls’ school. Eight firefighters attended the blaze, which badly damaged ten rooms on the ground floor and first floor, where the company’s administrative and storage areas were housed. Other rooms were affected by smoke and water.

The cause of the fire is as yet unknown, but West Yorkshire police have found evidence of a break-in in the building, the car park of which serves as a meeting point for local young people at night. The building had been a temporary home for Northern Ballet Theatre whilst work on their new home in the city’s arts district is completed. The company’s chief sponsor, Halifax Bank has now provided emergency offices.

Romeo and Juliet is due to open in Norwich on April 24. Chief Executive of Northern Ballet, Mark Skipper told the Guardian newspaper: “I have seen all my administration go up in smoke, including every file in my computer which just melted. We have now got three weeks to replace or repair all the Romeo and Juliet costumes”.

Northern Ballet Theatre is one of Britain’s leading classical ballet companies, employing around 100 artistic and administrative staff, dancers, musicians, stage and wardrobe technicians. The dancers of the company were at High Wycombe at the time of the fire, performing in the current season of Jekyll and Hyde.